Nato will not be deterred from its military action in Libya by Muammar Gaddafi’s threats to take the war to Europe, the US secretary of state, Hillary Clinton, has said.

Clinton brushed aside Gaddafi’s warning that unless air strikes against his regime stopped, he would retaliate with attacks on civilians in Europe.

Speaking in Spain on the last leg of a three-nation European tour, she said: “Instead of issuing threats, he should be putting the wellbeing and interests of his own people first. He should step down from power.”

Her comments came as Nato announced it was ramping up airstrikes in the western half of Libya, which is still largely under Gaddafi’s control.